The present invention relates to folding blade knives and, more particularly, to knives having one or more blades pivotally movable between open and closed positions with respect to a handle piece with biasing means assisting in such movement.
The prior art includes many examples of folding knives wherein a blade is pivotally mounted upon a handle piece for movement for movement between open and closed positions with a spring, wire, or other biasing means assisting in such movement. In one type of spring assisted blade opening, typified by U.S. Pat. Nos. 6,145,202, 6,397,476, 5,802,722, and 6,308,420, the blade must be moved manually away from the fully open or fully closed position for a portion of its travel before the biasing element takes effect to complete the blade movement. The biasing element may be in the form of a wire having opposite end portions bent to extend through openings or grooves in the handle and blade, or have a portion engaging a roller mounted upon the blade tang with a central axis parallel to and spaced from the pivot axis of the blade.
In general, the object of the present invention is to provide a novel and improved folding blade knife having a spring for assisting in pivotal movement of the blade through terminal portions of its travel between the open and closed positions.
A further object is to provide a knife having a blade pivotally mounted upon a handle piece for movement between fully open and closed positions wherein the blade is moved manually for an initial portion of its travel from one position toward the other and is then moved by spring action for the remainder of such travel, wherein the knife incorporates novel and improved biasing means providing the assisted blade movement.
Another object is to provide a folding blade knife having a cantilever spring and cam mechanism for assisting blade movement from partly to fully open and closed positions.
Other objects will partly be obvious and will partly appear hereinafter.